Pilot-aided multiuser detection in CDMA using the belief propagation algorithm

Application of the belief propagation algorithm for multi-user detection in code-division multiple access for the case of unknown channels is investigated. A new method is proposed where the unknown channel parameters are nodes in the graph, whose posterior distributions are to be calculated jointly with that of transmitted symbols. It is observed that the iterative algorithm, which is amenable to fast parallel implementation, has comparable performance with that of matrix-inversion based iterative algorithms.